With the advent of the information age, there is an increasing need to transmit large quantities of information among a multitude of customer terminals. The information, in the form of digital signals, customarily represents voice communication, video, facsimile, and/or bulk data transfers.
While the existing public-switched telecommunication networks can offer access to a number of the customer terminals requiring wideband service, most digital communication within the switched network is limited to 64 Kilobits per second (Kbps) due to the constraints imposed by existing switching and transmission facilities.
In those specific applications requiring greater bandwidth, private line facilities can be provided between selected customer terminals. Such private line wideband facilities, however, are costly, and since they only serve a few terminals, they are frequently idle and not fully utilized.
Combining several narrowband channels to form a wideband facility between customer terminals via the public-switched telecommunications network has been suggested in the prior art. However, correcting any time frame misalignment that may occur between the combined channels required the initial use of a test signal to detect time frame misalignment and a data recovery unit to compute any time frame misalignment and to introduce delay in selected ones of the narrowband channels to recorrelate the data into its original pattern. In addition to introducing costly equipment to the network, the prior art did not address the problem of how to correct for any time frame misalignment that may occur after an initial correction is made. Furthermore, significantly the art does not solve the problem of how to correct for time slot data delay from one time frame to another on the same channel. As a result, data is not received in the same order as it was transmitted.